Surface Marker Buoy and Air Share

[danvolker]

Remind me why I want to swim in circles rather than relax...

We do our decos in bluewater after these deep dives ( you are drifiting over 400 plus pretty soon much of the time) to enhance depth precision( from horizontal body swimming position it is easy to stay precisly at a given deco depth), and, your lungs are a MUCH more effective bubble filter when horizontal in the water collum, rather than vertical ( this is from Hydrostatic Lung Loading, where blood flow is much better for your lungs to function optimally at horizontal in water, than in vertical position). I have always preferred how I feel after hour long decos when I do mild swimming the whole time, versus vegetating on an anchor line...though with our currents, this was rarely ever considered...it did happen a few times in the distant past.


When I used to spearfish on the deep dives ( and sometimes kept a fish with me rather than sending it up) , you would be surprised how many of the divers who used to read books during deco, began spinning 360's nearly the entire time, and quickly stopped complaining about how boring the deco was

Regards.
DanV

After a 60 foot dive, my ascent would still have me circling....better bubble filtering and it is just a habit I like.

 

[DaleC]

Hi Soaked,

If you are sharing air I assume you are a two man team so why doesn't the long hose diver inflate the SMB while the necklaced diver manages the reel/spool.

 

[MXGratefulDiver]

We do our decos in bluewater after these deep dives ( you are drifiting over 400 plus pretty soon much of the time) to enhance depth precision( from horizontal body swimming position it is easy to stay precisly at a given deco depth), and, your lungs are a MUCH more effective bubble filter when horizontal in the water collum, rather than vertical ( this is from Hydrostatic Lung Loading, where blood flow is much better for your lungs to function optimally at horizontal in water, than in vertical position). I have always preferred how I feel after hour long decos when I do mild swimming the whole time, versus vegetating on an anchor line...though with our currents, this was rarely ever considered...it did happen a few times in the distant past.


When I used to spearfish on the deep dives ( and sometimes kept a fish with me rather than sending it up) , you would be surprised how many of the divers who used to read books during deco, began spinning 360's nearly the entire time, and quickly stopped complaining about how boring the deco was

Regards.
DanV

After a 60 foot dive, my ascent would still have me circling....better bubble filtering and it is just a habit I like.

Hmmmm ... I and everybody I've ever done a tech dive with do our deco while hovering in a horizontal position. If I'm pushing a 1.6 PPO2, I won't want to be swimming ... I'd prefer to just veg out and relax. If we're coming up a line we don't hang on the line ... we use it for visual reference only. If we're drifting, we shoot a bag so the boat can follow our progress.

Maybe it's a difference between east coast and west coast conditions/mentality ... but I don't know anyone out here who deco's while hanging vertically on an ascent line ... not even the old-school dudes or the RB divers. Nor have I ever seen anybody doing a swimming deco. I'm sure it's an OK thing to do, it just never occurred to me that I should ... I like just establishing my position and relaxing ...

... Bob (Grateful Diver)

 

[MXGratefulDiver]

Hi Soaked,

If you are sharing air I assume you are a two man team so why doesn't the long hose diver inflate the SMB while the necklaced diver manages the reel/spool.

... a smaller bag's a better idea under most conditions her and Sam will be diving in. If you're diving out in Neah Bay or on the west side of Van Isle, a big bag's needed due to the windward conditions typically encountered out there. But in Puget Sound or along the Sunshine Coast, conditions will rarely be bad enough to need something bigger than the 3-foot bag to be visible.

And the smaller bags are just so much easier to deploy ...

... Bob (Grateful Diver)

 

[Soakedlontra]

Hi Soaked,

If you are sharing air I assume you are a two man team so why doesn't the long hose diver inflate the SMB while the necklaced diver manages the reel/spool.

Let me think about this...

If the needer is under control and not stressed out he/she may be able to inflate the SMB without crewing things up but if not it is all up to the donor because I can imagine that if the needer is really stressed out and panicking, he/she won't be able to perform any tasks at all! In that case a better option may be to forget about inflating the SMB altogether...

When we practice these skills we are in a controlled environment and because we have not experienced any real emergency situations so far (let's touch wood!) we have no idea how the needer is going to respond and at what level of stress he/she is going to have. I guess we have to practice in two different ways keeping both scenarios in mind...

 

[Blackwood]

We do our decos in bluewater after these deep dives ( you are drifiting over 400 plus pretty soon much of the time) to enhance depth precision( from horizontal body swimming position it is easy to stay precisly at a given deco depth), and, your lungs are a MUCH more effective bubble filter when horizontal in the water collum, rather than vertical ( this is from Hydrostatic Lung Loading, where blood flow is much better for your lungs to function optimally at horizontal in water, than in vertical position). I have always preferred how I feel after hour long decos when I do mild swimming the whole time, versus vegetating on an anchor line...though with our currents, this was rarely ever considered...it did happen a few times in the distant past.


When I used to spearfish on the deep dives ( and sometimes kept a fish with me rather than sending it up) , you would be surprised how many of the divers who used to read books during deco, began spinning 360's nearly the entire time, and quickly stopped complaining about how boring the deco was

Regards.
DanV

After a 60 foot dive, my ascent would still have me circling....better bubble filtering and it is just a habit I like.

Interesting. So are you circling eachother (buddy teams)?

I tend to be as relaxed as possible. Horizontal yes, swimming no (unless to keep position relative to my team or to the line). I guess if you've got a long time to do maybe it keeps your mind occupied. Thus far I've only done about 45 minutes max, and that was due to a failed deco bottle.

 

[Peter Guy]

D.V. wrote

this is from Hydrostatic Lung Loading, where blood flow is much better for your lungs to function optimally at horizontal in water, than in vertical position

I am NOT a student of physiology so please help me out here. What I have read about H.S.L. refers to work of breathing issues and has nothing to do with blood flow so obviously I haven't been reading the right things!

Please explain for me (and in simple terms if possible!) how blood flow in, and around, the lungs is effected by body position in the water? I can (sort of) wrap my mind around the idea that being verticle would tend to want to make you breathe "shallower" (i.e., "off the top of your lungs") since the pressure differential between your mouth (when using a single hose regulator) and the bottom of your lungs would be greatest. The ambient pressure of the gas entering your respiratory system (mouth) would be a little bit less than the ambient pressure at the bottom of your lungs (perhaps 0.4 PSI? and I have no idea what that would be in inches of mercury OR how much negative pressure one's natural breathing creates so I don't know what that 0.4 PSI means in the real world). But I don't see how that would effect blood flow?

Or is it just that, perhaps, when vertical, one doesn't fully inflate one's lungs as easily as when horizontal -- thus yielding the lungs to be a bit less efficient and having less total lung surface area exposed to the inhaled/exhaled gas?

 

[DaleC]

If the needer is under control and not stressed out he/she may be able to inflate the SMB without crewing things up but if not it is all up to the donor because I can imagine that if the needer is really stressed out and panicking, he/she won't be able to perform any tasks at all!

Perhaps, but I thought the reason for practicing the skills was so that the stress would be reduced. With good team dynamics there should be no OOA's and if there are they should really be (somewhat) non events. The team should be close enough to each other for rapid AAS deployment and OOA's generally don't happen instantly except when the dip tube clogs or with some rare regulator failure in the closed mode. Usually there are a couple/few breaths with increasing resistance. I've experienced this at 100' and several times at 30-40'.

Another skill you may want to practice (in a controlled setting) is actually breathing some bottles down to simulate an OOA; then you will know the sensation that precedes the event. It's not that bad when you know what's coming. At 100' I felt the resistance as I was videoing and switched regs without stopping (not that I recommend that course of action ).

Anyways, it's great that you are thinking about these things. That fact alone indicates that you and your teammate will probably perform well in any event.



On another note to do with this swimming idea. I know nothing about offgassing physics perse but I've always wondered (as I'm hanging around) if I would offgas more effectively by being passive or moderately active (like slow swimming). Would moderate exertion speed up the rate that N is expelled (increased respiration or cellular activity) or does it not have any effect in that regard? If I aggitate an open cola bottle it seems that the CO2 is released faster (I know that doesn't count as dive physiology :bonk: )

 

[danvolker]

Interesting. So are you circling eachother (buddy teams)?

Always in visual, nearby....spiral is mainly so we don't swim a mile or two away from any other divers not in our group, but from the same boat....I suppose we could swim a compass bearing toward shore if we were the only group..or straight out into deeper water...

Regards,
DanV

 

[danvolker]

D.V. wrote
I am NOT a student of physiology so please help me out here. What I have read about H.S.L. refers to work of breathing issues and has nothing to do with blood flow so obviously I haven't been reading the right things!

Please explain for me (and in simple terms if possible!) how blood flow in, and around, the lungs is effected by body position in the water? I can (sort of) wrap my mind around the idea that being verticle would tend to want to make you breathe "shallower" (i.e., "off the top of your lungs") since the pressure differential between your mouth (when using a single hose regulator) and the bottom of your lungs would be greatest. The ambient pressure of the gas entering your respiratory system (mouth) would be a little bit less than the ambient pressure at the bottom of your lungs (perhaps 0.4 PSI? and I have no idea what that would be in inches of mercury OR how much negative pressure one's natural breathing creates so I don't know what that 0.4 PSI means in the real world). But I don't see how that would effect blood flow?

Or is it just that, perhaps, when vertical, one doesn't fully inflate one's lungs as easily as when horizontal -- thus yielding the lungs to be a bit less efficient and having less total lung surface area exposed to the inhaled/exhaled gas?

Hi Peter,
My understanding is that blood flow in the lungs will be effected to a greater degree when the body is vertical ( in water). Pressure differential between the bottom of the lungs and the top of the lungs when vertical, will prevent optimal bloodflow at alveoli level , compared to best bloodflow when horizontal ( less pressure differential with smaller top to bottom distance when lungs are oriented this way) ...the lungs being a powerful "filter" for removing bubbles, and the increased efficiency of horizontal being one more safety tool at our disposal. This was a WKPP idea.
REgards,
DanV